Process for the preparation of 3-aryl-benzofuranones

ABSTRACT

Process for the preparation of compounds of formula (I), wherein the general symbols are as defined in claim  1 , which process comprises reacting a compound of formula (V), wherein the general symbols are as defined in claim  1 , with carbon monoxide in the presence of a catalyst.

This Application is a 371 PCT/EP99,04417 filed Jun. 15, 1999.

The present invention relates to a novel process for the preparation of 3-aryl-benzofuran-ones, which are suitable for stabilising organic materials against oxidative, thermal or light-induced degradation.

The best processes hitherto for the preparation of 3-aryl-benzofuranones are described, for example, in U.S. Pat. No. 4,325,863 and U.S. Pat. No. 5,607,624.

The process disclosed in U.S. Pat. No. 4,325,863 (Example 1, column 8, lines 35-45) for the preparation of 3-phenyl-3H-benzofuran-2-ones, for example 5,7-di-tert-butyl-3-phenyl-3H-benzofuran-2-one of formula C, comprises reacting the 2,4-di-tert-butylphenol of formula A with the mandelic acid of formula B, with removal of water.

A disadvantage of that process is that it requires the use of mandelic acids substituted on the phenyl ring or heterocyclic mandelic acids. Not very many of those mandelic acids are known from the literature, however, and the known synthesis procedures for the preparation thereof are relatively complicated.

The process disclosed in U.S. Pat. No. 5,607,624 (Example 1, column 24) for the preparation of 3-phenyl-3H-benzofuran-2-ones substituted on the 3-phenyl ring, for example 5,7-di-tert-butyl-3-(2,5-dimethyl-phenyl)-3H-benzofuran-2-one of formula F, comprises reacting the 5,7-di-tert-butyl-3-hydroxy-3H-benzofuran-2-one of formula D with p-xylene of formula E, with removal of water.

A disadvantage of that process is that, for the preparation of unsubstituted 3phenyl-benzo-furanone derivatives, it requires the use of benzene, which is carcinogenic, instead of p-xylene.

R. F. Heldeweg, H. Hogeveen, J. Amer. Chem. Soc. 98 (19), 6040-6042 (1976) disclose novel rhodium-catalyzed additions of carbon monoxide to reactive dienes and enones with formation of five-membered rings.

There is therefore still a need to find an efficient process for the preparation of 3aryl-benzofuranones that does not have the disadvantages mentioned above.

The present invention therefore relates to a process for the preparation of compounds of formula I

wherein, when n is 1,

R¹ is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by fluorine, hydroxy, C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, di-(C₁-C₄alkyl)amino, phenyl, benzyl, benzoyl or by benzoyloxy or R₁ is a radical of formula II or III

when n is 2,

R₁ is phenylene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl or by fluorine; or is —R₆—X—R₇—,

R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅-alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di-(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

 C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV

wherein R₁ is as defined above for the case where n=1,

R₆ and R₇ are each independently of the other phenylene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl,

R₈ is C₁-C₈alkyl,

R₉ is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

 C₁-C₁₈alkoxy or

R₁₀ and R₁₁ are each independently of the other hydrogen, CF₃, C₁-C₁₂alkyl or phenyl, or R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C₁-C₄alkyl groups;

R₁₂ and R₁₃ are each independently of the other hydrogen or C₁-C₁₈alkyl,

R₁₄ is hydrogen or C₁-C₁₈alkyl,

R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

 C₁-C₂₅alkoxy; C₂-C₂₅alkoxy interrupted by oxygen, sulfur or by

 C₁-C₂₅alkylthio, C₇-C₉phenylalkyl, C₇-C₉phenylalkoxy, unsubstituted or C₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substituted phenoxy; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkoxy; di(C₁-C₄alkyl)amino, C₁-C₂₅-alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

 C₁-C₂₅alkanoyloxy; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

 C₁-C₂₅alkanoylamino, C₆-C₉cycloalkylcarbonyl, C₆-C₉cycloalkylcarbonyloxy, benzoyl or C₁-C₁₂alkyl-substituted benzoyl; benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy;

R₂₄ is hydrogen, C₁-C₄alkyl, or unsubstituted or C₁-C₄alkyl-substituted phenyl,

R₂₅ and R₂₆ are hydrogen, C₁-C₄alkyl or phenyl, with the proviso that at least one of the radicals R₂₅ and R₂₆ is hydrogen,

R₂₇ and R₂₈ are each independently of the other hydrogen, C₁-C₄alkyl or phenyl,

R₂₉ is hydrogen or C₁-C₄alkyl,

R₃₀ is hydrogen, unsubstituted or C₁-C₄alkyl-substituted phenyl; C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

 C₇-C₉phenylalkyl unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups; or C₇-C₂₅phenylalkyl interrupted by oxygen, sulfur or by

 and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups,

R₃₁ is hydrogen or C₁-C₄alkyl,

R₃₂ is hydrogen, C₁-C₂₅alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

 C₂-C₂₅alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group; C₆-C₉cyclo-alkylcarbonyl, thenoyl, furoyl, benzoyl or C₁-C₁₂alkyl-substituted benzoyl;

R₃₃ is hydrogen or C₁-C₈alkyl,

R₃₄ is a direct bond, C₁-C₁₈alkylene; C₂-C₁₈alkylene interrupted by oxygen, sulfur or by

 C₂-C₂₀alkylidene, C₇-C₂₀phenylalkylidene, C₅-C₈cycloalkylene, C₇-C₈bicyclo-alkylene, unsubstituted or C₁-C₄alkyl-substituted phenylene,

R₃₅ is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

 C₁-C₁₈alkoxy or

R₃₆ is oxygen, —NH— or

R₃₇ is C₁-C₁₈alkyl or phenyl,

M is an r-valent metal cation,

X is a direct bond, oxygen, sulfur or —NR₁₄—,

n is 1 or 2,

p is 0, 1 or 2,

q is 1, 2, 3, 4, 5 or 6,

r is 1, 2 or 3, and

s is 0, 1 or 2,

which process comprises reacting a compound of formula V

 wherein

 R₁ and n are as defined above,

 R₂, R₃, R′₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈-cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

 C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R′₄ or the radicals R′₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R′₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen,

 R′₄ is additionally a radical of formula VI

 wherein R₁ is as defined above for the case where n=1,

 with carbon monoxide in the presence of a catalyst.

Alkanoyl having up to 25 carbon atoms is a branched or unbranched radical, for example formyl, acetyl, propionyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, pentadecanoyl, hexadecanoyl, heptadecanoyl, octadecanoyl, icosanoyl or docosanoyl. Alkanoyl has preferably from 2 to 18, especially from 2 to 12, e.g. from 2 to 6, carbon atoms. Special preference is given to acetyl.

C₂-C₂₅Alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group is, for example, (CH₃CH₂O)₂POCH₂CO—, (CH₃O)₂POCH₂CO—, (CH₃CH₂CH₂CH₂O)₂POCH₂CO—, (CH₃CH₂O)₂POCH₂CH₂CO—, (CH₃O)₂POCH₂CH₂CO—, (CH₃CH₂CH₂CH₂O)₂POCH₂CH₂CO—, (CH₃CH₂O)₂PO(CH₂)₄CO—, (CH₃CH₂O)₂PO(CH₂)₈CO— or (CH₃CH₂O)₂PO(CH₂)₁₇CO—.

Alkanoyloxy having up to 25 carbon atoms is a branched or unbranched radical, for example formyloxy, acetoxy, propionyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy, decanoyloxy, undecanoyloxy, dodecanoyloxy, tridecanoyloxy, tetradecanoyloxy, pentadecanoyloxy, hexadecanoyloxy, heptadecanoyloxy, octadecanoyloxy, icosanoyloxy or docosanoyloxy. Preference is given to alkanoyloxy having from 2 to 18, especially from 2 to 12, e.g. from 2 to 6, carbon atoms. Special preference is given to acetoxy.

C₃-C₂₅Alkenoyloxy interrupted by oxygen, sulfur or by

is, for example, CH₃OCH₂CH₂CH═CHCOO— or CH₃OCH₂CH₂OCH═CHCOO—.

C₃-C₂₅Alkanoyl interrupted by oxygen, sulfur or by

is, for example, CH₃—O—CH₂CO—, CH₃—S—CH₂CO—, CH₃—N(CH₃)—CH₂CO—, CH₃—O—CH₂CH₂—O—CH₂CO—, CH₃—(O—CH₂CH₂—)₂O—CH₂CO—, CH₃—(O—CH₂CH₂—)₃—O—CH₂CO— or CH₃—(O—CH₂CH₂—)₄—CH₂CO—.

C₃-C₂₅Alkanoyloxy interrupted by oxygen, sulfur or by

is, for example, CH₃—O—CH₂COO—, CH₃—S—CH₂COO—, CH₃—N(CH₃)—CH₂COO—, CH₃—O—CH₂CH₂—O—CH₂COO—, CH₃—(O—CH₂CH₂—)₂O—CH₂COO—, CH₃—(O—CH₂CH₂—)₃O—CH₂COO— or CH₃—(O—CH₂CH₂—)₄O—CH₂COO—.

C₆-C₉Cycloalkylcarbonyl is, for example, cyclopentylcarbonyl, cyclohexylcarbonyl, cycloheptylcarbonyl or cyclooctylcarbonyl. Preference is given to cyclohexylcarbonyl.

C₆-C₉Cycloalkylcarbonyloxy is, for example, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, cycloheptylcarbonyloxy or cyclooctylcarbonyloxy. Preference is given to cyclohexylcarbonyloxy.

C₁-C₁₂Alkyl-substituted benzoyl, which carries preferably from 1 to 3, especially 1 or 2, alkyl groups, is, for example, o-, m- or p-methylbenzoyl, 2,3-dimethylbenzoyl, 2,4-dimethylbenzoyl, 2,5-dimethylbenzoyl, 2,6-dimethylbenzoyl, 3,4-dimethylbenzoyl, 3,5-dimethylbenzoyl, 2-methyl-6-ethylbenzoyl, 4-tert-butylbenzoyl, 2-ethylbenzoyl, 2,4,6-trimethylbenzoyl, 2,6-dimethyl-4-tert-butylbenzoyl or 3,5-di-tert-butylbenzoyl. Preferred substituents are C₁-C₈-alkyl, especially C₁-C₄alkyl.

C₁-C₁₂Alkyl-substituted benzoyloxy, which carries preferably from 1 to 3, especially 1 or 2, alkyl groups, is, for example, o-, m- or p-methylbenzoyloxy, 2,3-dimethylbenzoyloxy, 2,4-dimethylbenzoyloxy, 2,5-dimethylbenzoyloxy, 2,6-dimethylbenzoyloxy, 3,4-dimethylbenzoyloxy, 3,5-dimethylbenzoyloxy, 2-methyl-6-ethylbenzoyloxy, 4-tert-butylbenzoyloxy, 2-ethylbenzoyloxy, 2,4,6-trimethylbenzoyloxy, 2,6-dimethyl-4-tert-butylbenzoyloxy or 3,5-di-tert-butylbenzoyloxy. Preferred substituents are C₁-C₈alkyl, especially C₁-C₄alkyl.

Alkyl having up to 25 carbon atoms is a branched or unbranched radical, for example methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, icosyl or docosyl. One of the preferred definitions for R₂ and R₄ is, for example, C₁-C₁₈alkyl. An especially preferred definition for R₄ is C₁-C₄alkyl.

C₂-C₂₅Alkyl interrupted by oxygen, sulfur or by

is, for example, CH₃—O—CH₂—, CH₃—S—CH₂—, CH₃—N(CH₃)—CH₂—, CH₃—O—CH₂CH₂—O—CH₂—, CH₃—(O—CH₂CH₂—)₂O—CH₂—, CH₃—(O—CH₂CH₂—)₃O—CH₂— or CH₃—(O—CH₂CH₂—)₄O—CH₂—.

C₇-C₉Phenylalkyl is, for example, benzyl, α-methylbenzyl, α,α-dimethylbenzyl or 2-phenylethyl. Preference is given to benzyl and α,α-dimethylbenzyl.

C₇-C₉Phenylalkyl unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups is, for example, benzyl, α-methylbenzyl, α,α-dimethylbenzyl, 2-phenylethyl, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl, 2,4-dimethylbenzyl, 2,6-dimethylbenzyl or 4-tertbutylbenzyl. Preference is given to benzyl.

C₇-C₂₅Phenylalkyl interrupted by oxygen, sulfur or by

and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alKyl groups is a branched or unbranched radical, for example phenoxymethyl, 2-methyl-phenoxymethyl, 3-methyl-phenoxymethyl, 4-methyl-phenoxymethyl, 2,4-dimethyl-phenoxymethyl, 2,3-dimethyl-phenoxymethyl, phenyl-thiomethyl, N-methyl-N-phenyl-aminomethyl, N-ethyl-N-phenyl-aminomethyl, 4-tert-butyl-phenoxymethyl, 4-tert-butyl-phenoxyethoxy-methyl, 2,4-di-tert-butyl-phenoxymethyl, 2,4-di-tert-butyl-phenoxyethoxymethyl, phenoxyethoxyethoxyethoxymethyl, benzyloxymethyl, benzyloxyethoxymethyl, N-benzyl-N-ethyl-aminomethyl or N-benzyl-N-isopropyl-aminomethyl.

C₇-C₉Phenylalkoxy is, for example, benzyloxy, α-methylbenzyloxy, α,α-dimethylbenzyloxy or 2-phenylethoxy. Preference is given to benzyloxy.

C₁-C₄Alkyl-substituted phenyl, which contains preferably from 1 to 3, especially 1 or 2, alkyl groups, is, for example, o-, m- or p-methylphenyl, 2,3-dimethyiphenyi, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2-methyl-6-ethylphenyl, 4-tert-butylphenyl, 2-ethylphenyl or 2,6-diethylphenyl.

C₁-C₄Alkyl-substituted phenoxy, which contains preferably from 1 to 3, especially 1 or 2, alkyl groups, is, for example, o-, m- or p-methylphenoxy, 2,3-dimethylphenoxy, 2,4-dimethylphenoxy, 2,5-dimethylphenoxy, 2,6-dimethylphenoxy, 3,4-dimethylphenoxy, 3,5-dimethylphenoxy, 2-methyl-6-ethylphenoxy, 4-tert-butylphenoxy, 2-ethylphenoxy or 2,6-diethylphenoxy.

Unsubstituted or C₁-C₄alkyl-substituted C₅-Cacycloalkyl is, for example, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl, tert-butylcyclohexyl, cycloheptyl or cyclooctyl. Preference is given to cyclohexyl and tert-butylcyclohexyl.

Unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkoxy is, for example, cyclopentyloxy, methylcyclopentyloxy, dimethylcyclopentyloxy, cyclohexyloxy, methylcyclohexyloxy, dimethylcyclohexyloxy, trimethylcyclohexyloxy, tert-butylcyclohexyloxy, cycloheptyloxy or cyclooctyloxy. Preference is given to cyclohexyloxy and tert-butylcyclohexyloxy.

Alkoxy having up to 25 carbon atoms is a branched or unbranched radical, for example methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, tetradecyloxy, hexadecyloxy or octadecyloxy. Preference is given to alkoxy having from 1 to 12, especially from 1 to 8, e.g. from 1 to 6, carbon atoms.

C₂-C₂₅Alkoxy interrupted by oxygen, sulfur or by

is for example, CH₃—O—CH₂CH₂O—, CH₃—S—CH₂CH₂O—, CH₃—N(CH₃)—CH₂CH₂O—, CH₃—O—CH₂CH₂—O—CH₂CH₂O —, CH₃—(O—CH₂CH₂—)₂O—CH₂CH₂O—, CH₃—(O—CH₂CH₂—)₃O—CH₂CH₂O— or CH₃—(O—CH₂CH₂—)₄O—CH₂CH₂O—.

Alkylthio having up to 25 carbon atoms is a branched or unbranched radical, for example methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, isobutylthio, pentylthio, isopentylthio, hexylthio, heptyithio, octylthio, decylthio, tetradecylthio, hexadecylthio or octadecylthio. Preference is given to alkyithio having from 1 to 12, especially from 1 to 8, e.g. from 1 to 6, carbon atoms.

Alkylamino having up to 4 carbon atoms is a branched or unbranched radical, for example methylamino, ethylamino, propylamino, isopropylamino, n-butylamino, isobutylamino or tert-butylamino.

Di(C₁-C₄alkyl)amino means also that the two radicals are each independently of the other branched or unbranched, for example, dimethylamino, methylethylamino, diethylamino, methyl-n-propylamino, methylisopropylamino, methyl-n-butylamino, methylisobutylamino, ethylisopropylamino, ethyl-n-butylamino, ethylisobutylamino, ethyl-tert-butylamino, diethylamino, diisopropylamino, isopropyl-n-butylamino, isopropylisobutylamino, di-n-butylamino or di-isobutylamino.

Alkanoylamino having up to 25 carbon atoms is a branched or unbranched radical, for example formylamino, acetylamino, propionylamino, butanoylamino, pentanoylamino, hexanoylamino, heptanoylamino, octanoylamino, nonanoylamino, decanoylamino, undecanoylamino, dodecanoylamino, tridecanoylamino, tetradecanoylamino, pentadecanoylamino, hexadecanoylamino, heptadecanoylamino, octadecanoylamino, icosanoylamino or docosanoylamino. Preference is given to alkanoylamino having from 2 to 18, especially from 2 to 12, e.g. from 2 to 6, carbon atoms.

C₁-C₁₈Alkylene is a branched or unbranched radical, for example methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, dodecamethylene or octadecamethylene. Preference is given to C₁-C₁₂alkylene, especially C₁-C₈alkylene. An especially preferred definition for R₅₆ is C₂-C₈alkylene, especially C₄-C₈alkylene, for example tetramethylene or pentamethylene.

C₂-C₁₈Alkylene interrupted by oxygen, sulfur or by

is, for example, —CH₂—O—CH₂—, —CH₂—S—CH₂—, —CH₂—N(CH₃)—CH₂—, —CH₂—O—CH₂CH₂—O—CH₂—, —CH₂—(O—CH₂CH₂—)₂O—CH₂—, —CH₂—(O—CH₂CH₂—)₃O—CH₂—, —CH₂—(O—CH₂CH₂—)₄O—CH₂— or —CH₂CH₂—S—CH₂CH₂—.

Alkylidene having from 2 to 20 carbon atoms is, for example, ethylidene, propylidene, butylidene, pentylidene, 4-methylpentylidene, heptylidene, nonylidene, tridecylidene, nonadecylidene, 1-methylethylidene, 1-ethylpropylidene or 1-ethylpentylidene. Preference is given to C₂-C₈alkylidene.

Phenylalkylidene having from 7 to 20 carbon atoms is, for example, benzylidene, 2-phenylethylidene or 1-phenyl-2-hexylidene. Preference is given to C₇-C₉phenylalkylidene.

C₅-C₈Cycloalkylene is a saturated hydrocarbon group having two free valences and at least one ring unit and is, for example, cyclopentylene, cyclohexylene, cycloheptylene or cyclooctylene. Preference is given to cyclohexylene.

C₇-C₈Bicycloalkylene is, for example, bicycloheptylene or bicyclooctylene.

Phenytene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl is, for example, 1,2-, 1,3- or 1,4-phenylene or 1,2-, 1,3-, 1,4-, 1,6-, 1,7-, 2,6- or 2,7-naphthylen is given to 1,4-phenylene.

A C₅-C₈cycloalkylidene ring substituted by C₁-C₄alkyl, which contains preferably from 1 to 3, especially 1 or 2, branched or unbranched alkyl group radicals, is, for example, cyclopentylidene, methylcyclopentylidene, dimethylcyciopentylidene, cyclohexylidene, methylcyclohexylidene, dimethylcyclohexylidene, trimethylcyclohexylidene, tert-butylcyclohexylidene, cycloheptylidene or cyclooctylidene. Preference is given to cyclohexylidene and tert-butylcyclohexylidene.

A mono-, di- or tri-valent metal cation is preferably an alkali metal cation, alkaline earth metal cation or aluminium cation, for example Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺ or Al⁺⁺⁺.

Dendrimeric, oligomeric or polymeric C₄-C₁₀₀hydrocarbon radicals are, for example, those such as are disclosed by R. Mülhaupt et al. in Angew. Chem., Int. Ed. 32 (9), 1306 (1993).

Of interest is a process for the preparation of compounds of formula I wherein,

when n is 2,

R₁ is phenylene or —R₆—X—R₇—,

R₆ and R₇ are phenylene, —X is oxygen or —NR₁₄—, and

R₁₄ is C₁-C₄alkyl.

Likewise of interest is a process for the preparation of compounds of formula I wherein R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl; C₂-C₁₈alkyl interrupted by oxygen or by sulfur; C₁-C₁₈alkoxy; C₂-C₁₈alkoxy interrupted by oxygen or by sulfur; C₁-C₁₈alkylthio, C₇-C₉phenylalkyl, C₇-C₉phenylalkoxy, unsubstituted or C₁-C₄alkyl-substituted phenyl; phenoxy, cyclohexyl, C₅-C₈cycloalkoxy, di(C₁-C₄-alkyl)amino, C₁-C₁₂alkanoyl; C₃-C₁₂alkanoyl interrupted by oxygen or by sulfur; C₁-C₁₂-alkanoyloxy; C₃-C₁₂alkanoyloxy interrupted by oxygen or by sulfur; C₁-C₁₂alkanoylamino, cyclohexylcarbonyl, cyclohexylcarbonyloxy, benzoyl or C₁-C₄alkyl-substituted benzoyl; benzoyloxy or C₁-C₄alkyl-substituted benzoyloxy;

R₂₄ is hydrogen or C₁-C₄alkyl,

R₂₅ and R₂₆ are hydrogen or C₁-C₄alkyl, with the proviso that at least one of the radicals R₂₅ and R₂₆ is hydrogen,

R₂₇ and R₂₈ are each independently of the other hydrogen or C₁-C₄alkyl,

R₂₉ is hydrogen,

R₃₀ is hydrogen, phenyl, C₁-C₁₈alkyl; C₂-C₁₈alkyl interrupted by oxygen or by sulfur; C₇-C₉-phenylalkyl; or C₇-C₁₈phenylalkyl interrupted by oxygen or by sulfur and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups,

R₃₁ is hydrogen or C₁-C₄alkyl,

R₃₂ is hydrogen, C₁-C₁₈alkanoyl; C₃-C₁₂alkanoyl interrupted by oxygen or by sulfur; C₂-C₁₂-alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group; C₆-C₉cycloalkylcarbonyl, benzoyl,

R₃₃ is hydrogen or C₁-C₄alkyl,

R₃₄ is C₁-C₁₂alkylene, C₂-C₈alkylidene, C₇-C₁₂phenylalkylidene, C₅-C₈cycloalkylene or phenylene,

R₃₅ is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

 or C₁-C₁₈alkoxy,

R₃₆ is oxygen or —NH—,

R₃₇ is C₁-C₈alkyl or phenyl, and

s is 1 or 2.

Of special interest is a process for the preparation of compounds of formula I wherein, when n is 1,

R₁ is phenanthryl, thienyl, dibenzofuryl, unsubstituted or C₁-C₄alkyl-substituted carbazolyl; or fluorenyl, or R₁ is a radical of formula II

wherein

R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, phenyl, benzoyl, benzoyloxy or

R₂₉ is hydrogen,

R₃₀ is hydrogen, phenyl or C₁-C₁₈alkyl,

R₃₁ is hydrogen or C₁-C₄alkyl, and

R₃₂ is hydrogen, C₁-C₁₂alkanoyl or benzoyl.

Likewise of special interest is a process for the preparation of compounds of formula I wherein

R₁₉ is hydrogen or C₁-C₄alkyl,

R₂₀ is hydrogen or C₁-C₄alkyl,

R₂₁ is hydrogen, fluorine, hydroxy, C₁-C₁₂alkyl, C₁-C₄alkoxy, C₁-C₄alkylthio, phenyl or —O—CH₂—CH₂—O—R₃₂,

R₂₂ is hydrogen or C₁-C₄alkyl,

R₂₃ is hydrogen or C₁-C₄alkyl, and

R₃₂ is C₁-C₄alkanoyl.

Of special interest is, more especially, a process for the preparation of compounds of formula I wherein

R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₂alkoxy, C₁-C₁₂alkylthio, C₁-C₄alkylamino, di-(C₁-C₄alkyl)amino, C₁-C₁₈alkanoyloxy, C₁-C₁₈alkanoylamino; C₃-C₁₈alkanoyloxy interrupted by oxygen, sulfur or by

C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₈alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV

R₈ is C₁-C₆alkyl,

R₉ is hydroxy, C₁-C₁₈alkoxy or

 R₁₀ and R₁₁ are methyl groups or, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C₁-C₄alkyl groups;

R₁₂ and R₁₃ are each independently of the other hydrogen or C₁-C₈alkyl, and

is 2,3,4,5 or 6.

Special preference is given to a process for the preparation of compounds of formula I wherein at least two of the radicals R₂, R₃, R₄ and R₅ are hydrogen.

Also very especially preferred is a process for the preparation of compounds of formula I wherein R₃ and R₅ are hydrogen.

Very special preference is given to a process for the preparation of compounds of formula I wherein

R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl, C₇-C₉phenylalkyl, phenyl, C₅-C₈cycloalkyl, C₁-C₆alkoxy, cyclohexylcarbonyloxy or benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉, or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV,

R₉ is hydroxy or C₁-C₁₈alkoxy, and

R₁₀ and R₁₁ are methyl groups or, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring.

Of preferential interest is a process for the preparation of compounds of formula I wherein

R₂ is C₁-C₁₈alkyl or cyclohexyl,

R₃ is hydrogen,

R₄ is C₁-C₄alkyl, cyclohexyl, —(CH₂)_(p)—COR₉ or a radical of formula IV,

R₅ is hydrogen,

R₉ is C₁-C₄alkyl,

R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a cyclohexylidene ring, and

p is 2.

Likewise of preferential interest is a process for the preparation of compounds of formula I wherein

R₂ is C₁-C₈alkyl or cyclohexyl,

R₃ is hydrogen,

R′₄ is C₁-C₄alkyl, cyclohexyl, —(CH₂)_(p)—COR₉ or a radical of formula VI,

R₅ is hydrogen,

R₉ is C₁-C₄alkyl,

R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a cyclohexylidene ring, and

p is 2.

Some of the monomeric compounds of formula V are present in the form of dimers of formula Va.

This equilibrium is temperature-dependent. The dimeric compound of formula Va may also be referred to as a Diels-Alder adduct. The dimeric compounds of formula Va can, together with further compounds of formula V, form trimeric, tetrameric or oligomeric compounds.

For the process according to the invention there may be used both the pure monomeric compound of formula V and the pure dimeric compound of formula Va, a mixture of the two compounds of formula V and Va or a mixture of any possible monomeric, dimeric, trimeric or oligomeric compounds derived from the compound of formula V. Under the reaction conditions, the dimeric, trimeric or oligomeric compounds derived from the compound of formula V form again the monomeric compound of formula V, which reacts with carbon monoxide and shifts the equilibrium towards the monomeric side.

Preferred reaction conditions for the process according to the invention are as follows:

The reaction may be carried out at an elevated temperature, especially at temperatures of from 50 to 200° C., in the melt or in a solvent, optionally under slight pressure.

Special preference is given to carrying out the reaction using a large molar excess of carbon monoxide. Special preference is therefore given to a process for the preparation of compounds of formula I wherein the ratio of molar quantities of the compound of formula V to carbon monoxide is from 1:1 to 1:5000.

Preference is given to using, as solvent, pressurised carbon monoxide, which at the same time constitutes the reactant.

As solvents there may, however, also be used solvents that do not participate in the reaction, for example hydrocarbons, ethers and aromatic compounds.

Preferred hydrocarbons are, for example, octane and commercially available isomeric fractions, for example hexane traction, petroleum ether and ligroin.

Preferred ethers are, for example, dibutyl ether, methyl tert-butyl ether and diethylene glycol dimethyl ether.

Examples of aromatic compounds are toluene and xylene.

A preferred catalyst for the process for the preparation of compounds of formula I is a metal catalyst, especially a metal catalyst that is capable of forming a complex with carbon monoxide, for example a transition metal catalyst.

Of preferential interest is a process for the preparation of compounds of formula I wherein the transition metal catalyst is a titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum or copper catalyst. Of special interest is a titanium, vanadium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel or palladium catalyst.

Especially preferred catalysts are, for example, V(CO)₆; Cr(CO)₆; Mn(CO)₆; Mn₂(CO)₁₀; Mn(CO)₅Br; Fe(CO)₅; Fe₂(CO)₉; Fe₃(CO)₁₂; Na₂Fe(CO)₄; [(cyclopentadienyl)Fe(CO)₂ ]₂; Co₂(CO)₈; Co₄(CO)₁₂; NaCo(CO)₄; Ni(CO)₄; Ni(CN)₂; NiPR′₃X′₂ wherein R′ is unsubstituted substituted phenyl, cyclohexyl or isopropyl and X′ is chlorine or bromine; Ni(PPh₃)₂(CO)₂; Pd(PPh₃)₄; Pd(PR′₃)₂X″₂ wherein R′ is as defined above and X″ is chlorine, bromine or iodine; Pd(PPh₂Me)₂Cl₂; Pd(AsPh₃)₂Cl₂; Pd(Br)(Ph)(PPh₃)₂; Pd(dipp)₂ wherein dipp is 1,3-bis(diiso-propylphosphino)propane; PdCl₂(R″CN)₂ wherein R″ is alkyl or phenyl; Pd(acetate)₂+PR′₃ wherein R′ is as defined above; R′₂PCH₂CH₂CH₂PR′₂ wherein R′ is as defined above; Pd₂(di-benzylidene acetone)₃+PR′₃ wherein R′ is as defined above; Li₂PdCl₄; PdCl₂+MgCl₂; PdCl₂+CuCl₂; HPtCl₆; [PtCl₂(SnCl₃)₂]²⁻; [Pt(SnCl₃)₅]³⁻; Pt(PPh₃)₂(CO)₂; Mo(CO)₆; Tc₂(CO)₁₀; Ru(CO)₅; Ru₃(CO)₁₂; RuCl₃; Rh₂(CO)₈; Rh₄(CO)₁₂; Rh₆(CO)₁₆; [Rh(CO)₂Cl]₂; [Rh(cyclooctadiene)Cl]₂; Rh₂(acetate)₄; Rh(PPh₃)₂Cl; W(CO)₆; Re₂(CO)₁₀; OS(CO)₅; Os₂(CO)₉; OS₃(CO)₁₂; Ir₂(CO)₈ and Ir₄(CO)₁₂.

A very especially preferred catalyst is, for example, tetrakis(triphenylphosphine)palladium(0).

Advantageously, the catalyst is used in an amount of from 0.01 to 20% by weight, especially from 0.1 to 10% by weight, e.g. from 0.1 to 5% by weight, based on the weight of the compound of formula V used.

The reaction can also be accelerated by addition of a catalytic amount of a protonic acid or Lewis acid.

Suitable protonic acids are, for example, acids of inorganic or organic salts, for example hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, p-toluenesultonic acid or carboxylic acids, for example formic acid, acetic acid and trifluoroacetic acid. Special preference is given to formic acid and trifluoroacetic acid.

Suitable Lewis acids are, for example, tin tetrachloride, aluminium chloride, zinc chloride, boron trifluoride etherate or anhydrides, for example carboxylic acid anhydrides, especially acetic anhydride. Special preference is given to tin tetrachloride, aluminium chloride and acetic anhydride.

The starting compounds of formula V are, in some instances, known or can be prepared in analogy to the method described by L. Jurd in J. Heterocyclic Chem. 25, 89-96 (1988).

A preferred process for the preparation of the starting compounds of formula V

wherein the general symbols are as defined above, comprises converting a compound of formula VII

wherein R₁ and n are as defined above,

R₂, R₃, R″₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R″₄ or the radicals R″₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R″₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R″₄ is additionally a radical of formula VIII

wherein R₁ is as defined above for the case where n=1, R₂, R₁₀ and R₁₁ are as defined above,

R₅₀ is —OR₅₁, —SR₅₂,

 R₅₁ is C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen or by sulfur; C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted phenyl,

R₅₂ is C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen or by sulfur; C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted phenyl,

R₅₃ and R₅₄ are each independently of the other hydrogen, C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen or by sulfur; C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; or a dendrimeric, oligomeric or polymeric C₄-C₁₀₀hydrocarbon radical,

R₅₅ is C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen or by sulfur; C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted phenyl; or a radical of formula IX

wherein R₁, R₂, R₃, R″₄, R₅ and n are as defined above,

R₅₆ is unsubstituted or C₁-C₄alkyl-substituted C₂-C₁₂alkylene, thermally or using light.

In that conversion the radical HR₅₀ is removed.

The reaction may be carried out at an elevated temperature, especially at temperatures of from 60 to 180° C., in the melt or in a solvent.

The reaction may be carried out in the melt or in a solvent, optionally under slight pressure.

As solvents there may be used solvents that do not participate in the reaction, for example hydrocarbons, ethers and aromatic compounds.

Preferred hydrocarbons are, for example, octane and commercially available isomeric fractions, for example hexane fraction, petroleum ether and ligroin.

Preferred ethers are, for example, dibutyl ether, methyl tert-butyl ether and diethylene glycol dimethyl ether.

Examples of aromatic compounds are toluene and xylene.

The reaction can also be accelerated by addition of a catalytic to excess amount of a protonic acid.

Suitable protonic acids are, for example, acids of inorganic or organic salts, for example hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, p-toluenesulfonic acid or carboxylic acids, for example acetic acid and trifluoroacetic acid. Special preference is given to trifluoroacetic acid.

Preference is given to the process for the preparation of compounds of formula V wherein

R₅₀ is —OR₅₁, —SR₅₂,

 R₅₁ is C₁-C₁₂alkyl; C₂-C₂alkyl interrupted by oxygen; benzyl, C₅-C₈cycloalkyl or phenyl,

R₅₂ is C₁-C₁₂alkyl; C₂-C₁₂alkyl interrupted by oxygen; benzyl, C₅-C₈cycloalkyl or phenyl,

R₅₃ and R₅₄ are each independently of the other hydrogen, C₁-C₁₂alkyl; C₂-C₁₂alkyl interrupted by oxygen; benzyl, C₅-C₈cycloalkyl, or a dendrimeric or oligomeric or polymeric C₄-C₅₀hydrocarbon radical,

R₅₅ is C₁-C₁₂alkyl; C₂-C₁₂alkyl interrupted by oxygen; benzyl, C₅‥C₈cycloalkyl, phenyl or a radical of formula IX

wherein R₁, R₂, R₃, R″₄, R₅ and n are as defined above, and

R₅₆ is C₂-C₈alkylene.

Special preference is given to the process for the preparation of compounds of formula V wherein

R₅₃ and R₅₄ are each independently of the other hydrogen, C₁-C₁₂alkyl, benzyl, cyclohexyl or a dendrimeric C₄-C₃₀hydrocarbon radical,

R₅₅ is C₁-C₁₂alkyl, benzyl, cyclohexyl, phenyl or a radical of formula IX

wherein R₁, R₂, R₃, R″₄, R₅ and n are as defined above, and

R₅₆ is C₄-C₈alkylene.

Of special interest is the process for the preparation of compounds of formula V wherein

R₅₃ and R₅₄ are each independently of the other C₁-C₁₂alkyl, benzyl or a dendrimeric C₄-C₃₀hydrocarbon radical, and

R₅₆ is C₄-C₆alkylene.

Special preference is given to the process for the preparation of compounds of formula V wherein the conversion to the compound of formula V is carried out in the presence of an acid, especially a carboxylic acid, for example acetic acid and trifluoroacetic acid.

The compounds of formula VII are known or can be obtained by methods known per se, such as those disclosed in Examples 1a, 2a and 3a.

The compounds of formula I can also be prepared in a so-called one-pot process, starting from the compounds of formula VII. In that process, the compounds of formula V are prepared in situ and, without being isolated, are reacted further with carbon monoxide in the presence of a catalyst.

The present invention therefore relates also to a process for the preparation of compounds of formula I

wherein the general symbols are as defined above, which process comprises converting a compound of formula VII

wherein the general symbols are as defined above, thermally or using light, to form a compound of formula V

wherein the general symbols are as defined above, and then, without its being isolated, reacting that compound with carbon monoxide in the presence of a catalyst.

The definitions of the general symbols for the one-pot process according to the invention are the same as for the other process of the invention discussed hereinbefore.

The preferred reaction parameters for the one-pot process correspond to the preferences for the two separate steps, which have already been discussed in detail.

The invention relates also to novel compounds of formula V

wherein, when n is 1,

R₁ is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by fluorine, hydroxy, C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, di(C₁-C₄alkyl)amino, phenyl, benzyl, benzoyl or by benzoyloxy or R₁ is a radical of formula II or III

when n is 2,

R₁ is phenylene or naphthylene each unsubstituted or substituted by C₃-C₄alkyl or by fluorine, or is —R₆—X—R₇—,

R₂, R₃, R′₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di-(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

 C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R′₄ or the radicals R′₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R′₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen,

R′₄ is additionally a radical of formula VI

wherein R₁ is as defined above for the case where n=1,

R₆ and R₇ are each independently of the other phenylene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl,

R₈ is C₁-C₈alkyl,

R₉ is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

 C₁-C₁₈alkoxy or

R₁₀ and R₁₁ are each independently of the other hydrogen, CF₃, C₁-C₁₂alkyl or phenyl, or R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C₁-C₄alkyl groups;

R₁₂ and R₁₃ are each independently of the other hydrogen or C₁-C₁₈alkyl,

R₁₄ is hydrogen or C₁-C₁₈alkyl,

R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

 C₁-C₂₅alkoxy; C₂-C₂₅alkoxy interrupted by oxygen, sulfur or by

 C₁-C₂₅alkylthio, C₇-C₉phenyl-alkyl, C₇-C₉phenylalkoxy, unsubstituted or C₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substituted phenoxy; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkoxy; di(C₁-C₄alkyl)amino, C₁-C₂₅-alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

 C₁-C₂₅alkanoyloxy; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

 C₁-C₂₅alkanoylamino, C₆-C₉cycloalkylcarbonyl, C₆-C₉cycloalkylcarbonyloxy, benzoyl or C₁-C₁₂alkyl-substituted benzoyl; benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy;

R₂₄ is hydrogen, C₁-C₄alkyl, or unsubstituted or C₁-C₄alkyl-substituted phenyl,

R₂₅ and R₂₆ are hydrogen, C₁-C₄alkyl or phenyl, with the proviso that at least one of the radicals R₂₅ and R₂₆ is hydrogen,

R₂₇ and R₂₈ are each independently of the other hydrogen, C₁-C₄alkyl or phenyl,

R₂₉ is hydrogen or C₁-C₄alkyl,

R₃₀ is hydrogen, unsubstituted or C₁-C₄alkyl-substituted phenyl; C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

 C₇-C₉phenylalkyl unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups; or C₇-C₂₅phenylalkyl interrupted by oxygen, sulfur or by

 and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups,

R₃₁ is hydrogen or C₁-C₄alkyl,

R₃₂ is hydrogen, C₁-C₂₅alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

 C₂-C₂₅alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group; C₆-C₉cycloalkylcarbonyl, thenoyl, furoyl, benzoyl or C₁-C₁₂alkyl-substituted benzoyl;

R₃₃ is hydrogen or C₁-C₈alkyl,

R₃₄ is a direct bond, C₁-C₁₈alkylene; C₂-C₁₈alkylene interrupted by oxygen, sulfur or by

 C₂-C₂₀alkylidene, C₇-C₂₀phenylalkylidene, C₅-C₈cycloalkylene, C₇-C₈bicyclo-alkylene, unsubstituted or C₁-C₄alkyl-substituted phenylene,

R₃₅is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

C₁-C₁₈alkoxy or

R₃₆ is oxygen, —NH— or

R₃₇ is C₁-C₁₈alkyl or phenyl,

M is an r-valent metal cation,

X is a direct bond, oxygen, sulfur or —NR₁₄—,

n is 1 or 2,

p is 0, 1 or 2,

q is 1, 2,3,4,5 or 6,

r is 1, 2 or 3, and

s is 0, 1 or 2,

with the proviso that when R₂ and R′₄ are hydrogen, methyl or tert-butyl or when R₃ and R′₄, together with the carbon atom to which they are bonded, form a benzo ring, at least one of the radicals R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ is other than hydrogen and R₁ is not unsubstituted naphthyl; with the proviso that R₁₉ and R₂₃ are other than hydroxy; and with the proviso that when R₂ and R′₄ are hydrogen, C₁-C₄alkyl or methoxy, R₂₀, R₂₁ and R₂₂ are other than methoxy.

The preferred general symbols for the novel compounds of formula V correspond to those in the preferred general symbols set out hereinbefore for the process according to the invention for the preparation of compounds of formula I.

The following Examples illustrate the invention further. Parts or percentages relate to weight.

EXAMPLE 1 Process for the Preparation of 5,7-di-tert-butyl-3-(3,4-dimethyl-phenyl)-3H-benzofuran-2-one (compound (101), Table 1).

a) Preparation of 2,4-di-tert-butyl-6-[dimethylamino-(3,4-dimethyl-phenyl)-methyl]-phenol (compound (201), Table 2).

A mixture of 26.82 g (0.13 mol) of 2,4-di-tert-butylphenol, 17.44 g (0.13 mol) of 3,4-di-methylbenzaldehyde and 22.0 g (0.20 mol) of a 40% aqueous solution of dimethylamine is heated in a closed vessel at 140° C. for 10 hours, the internal pressure rising to 4 bar. After cooling to room temperature, the reaction mixture is poured into 100 ml of water and extracted twice using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from isopropanol yields 28.25 g (59%) of 2,4-di-tert-butyl-6-[dimethylamino-(3,4-dimethyl-phenyl)-methyl]-phenol, m.p. 82-85° C., (compound (201), Table 2). Molecular weight C₂₅H₃₇NO (367.58). Analysis, calculated: C 81.69; H 10.15; N 3.81%. Analysis, found: C 81.78; H 10.05; N 3.80%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.18 (s, 9H); 1.43 (s, 9H); 221 (s, 6H); 2.24 (s, 6H); 4.27 (s, 1H); 6.74 (d, 1H); 7.11 (m, 4H); 12.43 (s, 1H).

b) Preparation of 2,4-di-tert-butyl-6-(3,4-dimethylbenzylidene)-cyclohexa-2,4-dienone (compound (301), Table 3) and the corresponding dimer (compound (401), Table 4).

60 ml of dry toluene and 2.9 g (25.5 mmol) of trifluoroacetic acid are added, under argon, to 6.24 g (17 mmol) of 2,4-di-tert-butyl-6-[dimethylamino-(3,4-dimethyl-pheny)-methyl]-phenol (compound (201), Table 2), prepared according to Example 1a. The reaction mixture is then maintained at 110° C. for 6 hours. After cooling to room temperature, the mixture is poured into 50 ml of water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from isopropanol yields 4.48 g (82%) of a mixture of 2,4-di-tert-butyl-6-(3,4-dimethyl-benzylidene)-cyclohexa-2,4-dienone (compound (301), Table 3) and the corresponding dimer (compound (401), Table 4), m.p. 214-217° C.

b′) Alternative process for the preparation of 2,4-di-tert-butyl-6-(3,4-dimethylbenzylidene)-cyclohexa-2,4-dienone (compound (301), Table 3) and the corresponding dimer (compound (401), Table 4).

A solution of 33.85 g (0.10 mol) of 3,5-di-tert-butyl-2-hydroxy-phenyl-(3,4-dimethyl-phenyl)-methanone (compound (203), Table 2) in 130 ml of dry tetrahydrofuran is slowly added dropwise, at 10° C., to a suspension of 7.57 g (0.20 mol) of lithium aluminium hydride in 150 ml of dry tetrahydrofuran, during which the reaction temperature should not exceed 15° C. After the addition, the reaction mixture is stirred for a further 30 minutes at room temperature. The excess of lithium aluminium hydride is destroyed by means of basic hydrolysis and the salts formed are filtered off. The residue is washed with tetrahydrofuran and the filtrates are concentrated using a vacuum rotary evaporator. The crude alcohol (compound (204), Table 2) is taken up in 100 ml of isopropanol; 0.2 g (1.05 mmol) of p-toluenesulfonic acid is added and the mixture is boiled under reflux for 18 hours. The reaction mixture is then concentrated using a vacuum rotary evaporator. Crystallisation of the residue from isopropanol yields 17.11 g (53%) of a mixture of 2,4-di-tert-butyl-6-(3,4-dimethyl-benzylidene)-cyclohexa-2,4-dienone (compound (301), Table 3) and the corresponding dimer (compound (401), Table 4), m.p. 214-217° C.

c) Preparation of 5,7-di-tert-butyl-3-(3,4-dimethyl-phenyl)-3H-benzofuran-2-one (compound (101), Table 1).

A solution of 645 mg (2.0 mmol) of a mixture of 2,4-di-tert-butyl-6-(3,4-dimethyl-benzylidene)-cyclohexa-2,4-dienone (compound (301). Table 3) and the corresponding dimer (compound (401), Table 4), prepared according to Example 1b, in 7 ml of toluene is degassed using argon and then 58 mg (0.05 mmol) of tetrakis(triphenylphosphine)-palladium(0) and 23 mg (0.20 mmol) of trifluoroacetic acid are added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 5 bar is then applied. The reaction mixture is maintained at 80° C. for 20 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from ethanol yields 464 mg (66%) of 5,7-di-tert-butyl-3-(3,4-dimethyl-phenyl)-3H-benzofuran-2-one (compound (101), Table 1), m.p. 130-132° C. Analysis, calculated: C 82.24; H 8.63%. Analysis, found: C 82.20; H 8.68%.

EXAMPLE 2 Process for the Preparation of 5,7-di-tert-butyl-3-phenyl-3H-benzofuran-2-one (compound (102), Table 1).

a) Preparation of 2,4-di-tert-butyl-6-(dimethylamino-phenyl-methyl)-phenol (compound (202), Table 2).

A mixture of 51.5 g (0.25 mol) of 2,4-di-tert-butylphenol, 26.5 g (0.25 mol) of benzaldehyde and 42.3 g (0.375 mol) of a 40% aqueous solution of dimethylamine is heated in a closed vessel at 140° C. for 10 hours, the internal pressure rising to 5 bar. After cooling to room temperature, the reaction mixture solidifies. Crystallisation of the residue from isopropanol yields 65.2 g (77%) of 2,4-di-tert-butyl-6-(dimethylamino-phenyl-methyl)-phenol, m.p. 120-123° C. (compound (202), Table 2). Molecular weight C₂₃H₃₃NO (339.52). Analysis, calculated: C 81.37; H 9.80; N 4.13%. Analysis, found: C 81.25; H 9.86; N 4.00%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.19 (s, 9H); 1.44 (s, 9H); 2.26 (s, 6H); 4.34 (s, 1H); 6.75 (d, 1H); 7.29 (m, 6H); 12.43 (s, 1H).

b) Preparation of 6-benzylidene-2,4-di-tert-butyl-cyclohexa-2,4-dienone (compound (302), Table 3) and the corresponding dimer (compound (402), Table 4).

60 ml of dry toluene and 2.9 g (25.5 mmol) of trifluoroacetic acid are added, under argon, to 5.75 g (17 mmol) of 2,4-di-tert-butyl-6-(dimethylamino-phenyl-methyl)-phenol (compound (202), Table 2), prepared according to Example 2a. The reaction mixture is then maintained at 110° C. for 6 hours. After cooling to room temperature, the mixture is poured into 50 ml of water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from acetonitrile yields 2.58 g (52%) of a mixture of 6-benzylidene-2,4-di-tert-butyl-cyclohexa-2,4-dienone (compound (302), Table 3) and the corresponding dimer (compound (402), Table 4), m.p. 164-166° C. Analysis, calculated for (302) and (402): C 85.67; H 8.90%. Analysis, found for (302) and (402): C 85.36; H 8.93%.

c) Preparation of 5,7-di-tert-butyl-3-phenyl-3H-benzofuran-2-one (compound (102), Table 1).

A solution of 589 mg (2.0 mmol) of a mixture of 6-benzylidene-2,4-di-tert-butyl-cyclohexa-2,4-dienone (compound (302), Table 3) and the corresponding dimer (compound (402), Table 4), prepared according to Example 2b, in 7 ml of toluene is degassed using argon and then 58 mg (0.05 mmol) of tetrakis(triphenylphosphine)palladium(0) and 23 mg (0.20 mmol) of trifluoroacetic acid are added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 5 bar is then applied. The reaction mixture is maintained at 80° C. for 20 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from isopropanol yields 580 mg (90%) of 5,7-di-tert-butyl-3-phenyl-3H-benzofuran-2-one (compound (102), Table 1), m.p. 116-119° C. Analysis, calculated: C 81.95; H 8.13%. Analysis, found: C 81.93; H 8.13%.

EXAMPLE 3 One-pot Process for the Preparation of Compound (103) (Table 1), Starting from Compound (205) (Table 2).

a) Preparation of compound (205) (Table 2).

A mixture of 45.67 g (0.12 mol) of 1,1′-bis[4,4′-(2-tert-butyl-1-hydroxy-phenyl)]cyclohexane, 25.5 g (0.24 mol) of benzaldehyde and 40.6 g (0.36 mol) of a 40% aqueous solution of dimethylamine is heated in a closed vessel at 140° C. for 10 hours, the internal pressure rising to 4.5 bar. After cooling to room temperature, the reaction mixture solidifies. Crystallisation of the residue from isopropanol yields 64.3 g (83%) of compound (205) (Table 2), m.p. 156-159° C. Molecular weight C₄₄H58N₂O₂ (646.96). Analysis, calculated: C 81.69; H 9.04; N 4.33%. Analysis, found: C 81.46; H 9.05; N 4.18%.

b) One-pot process for the preparation of compound (103) (Table 1), starting from compound (205) (Table 2).

A solution of 6.47 g (0.01 mol) of compound (205), prepared according to Example 3a, in 60 ml of dry toluene is degassed using argon and then 0.87 g (0.75 mmol) of tetrakis(triphenylphosphine)palladium(0) and 3.43 g (0.03 mol) of trifluoroacetic acid are added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 7.5 bar is then applied. The reaction mixture is maintained at 140° C. for 18 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Crystallisation of the residue from isopropanol yields 4.30 g (70%) of compound (103) (Table 1), m.p. 199-202° C. Empirical formula C₄₂H₄₄O₄. Analysis, calculated: C 82.32; H 7.24%. Analysis, found: C 81.91; H 7.20% ¹HNMR (300 MHz, CDCl₃, ppm): 1.34 (s, 18H); 1.48 (m, 6H); 2.17 (m, 4H); 4.80 (s, 2H); 6.94 (s, 2H); 7.14 (m, 6H); 7.29 (m, 6H).

EXAMPLE 4 One-pot Process for the Preparation of Compound (102) (Table 1), Starting from Compound (202) (Table 2).

A solution of 640 mg (1.89 mmol) of compound (202), prepared according to Example 2a, in 10 ml of dry toluene is degassed using argon and then 55 mg (0.05 mmol) of tetrakis(triphenylphosphine)palladium(0) and 323 mg (2.83 mmol) of trifluoroacetic acid are added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 8 bar is then applied. The reaction mixture is maintained at 140° C. for 19 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Filtration of the residue on silica gel using ethyl acetate and crystallisation of the pure fractions from isopropanol yields 561 mg (92%) of compound (102) (Table 1), m.p. 116-119° C. Analysis, calculated: C 81.95; H 8.13%. Analysis, found: C 81.90; H 8.15%.

Compound (102) (Table 1) may also be obtained in analogy to Example 4 using acetic anhydride instead of trifluoroacetic acid.

EXAMPLE 5 Process for the Preparation of Compound (104), Table 1.

a) Preparation of compound (206), Table 2.

Compound (206), Table 2, m.p. 205-206° C., is obtained in analogy to Example 1a using 0.065 mol of terephthalaldehyde (Fluka 86410) instead of 3,4-dimethylbenzaldehyde. Molecular weight C₄₀H₆₀N₂O₂ (600.932). Analysis, calculated: C 79.95; H 10.06; N 4.66%. Analysis, found: C 80.22; H 10.01; N 4.70%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.16 (s, 18H); 1.41 (s, 18H); 2.21 (s, 12H); 4.27 (s, 2H); 6.69 (d, 2H); 7.13 (d, 2H); 7.35 (s, 4H); 12.38 (s, 2H).

b) Preparation of compound (104), Table 1.

A solution of 1.14 g (1.89 mmol) of compound (206), prepared according to Example 5a, in 10 ml of dry toluene is degassed using argon and then 55 mg (0.05 mmol) of tetrakis(triphenylphosphine)palladium(0) and 348 mg (7.56 mmol) of formic acid are added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 8 bar is then applied. The reaction mixture is maintained at 110° C. for 4 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Filtration of the residue on silica gel using ethyl acetate and crystallisation of the pure fractions from isopropanol yields 942 mg (88%) of compound (104) (Table 1), m.p. 212-215° C. Molecular weight C3H₄₆0₄ (566.784). ¹HNMR (300 MHz, CDCl₃, ppm): 1.28 (s, 18H); 1.42 (s, 18H): 4.82 (s, 2H); 7.05 (d, 2H); 7.25 (s, 4H); 7.32 (d, 2H).

EXAMPLE 6 Process for the Preparation of Compound (102), Table 1.

a) Preparation of compound (208), Table 2.

37.46 g (0.44 mol) of piperidine are added dropwise, at room temperature, to a solution of 21.22 g (0.20 mol) of benzaldehyde in 70 ml of toluene; slight exothermicity is observed. The slightly yellow-coloured solution is boiled under reflux for 2 hours; approximately 4 ml of water are separated off using a water separator, and a solution of 39.20 g (0.19 mol) of 2,4-di-tert-butylphenol in 30 ml of toluene is then added dropwise. The reaction mixture is boiled at reflux for a further hour and then cooled to room temperature; the solvent is distilled off using a vacuum rotary evaporator. Crystallisation of the residue from toluene yields 50.14 g (70%) of compound (208) (Table 2), m.p. 140-141° C. Molecular weight C₂₆H₃₇NO (379.588). Analysis, calculated: C 82.27; H 9.82; N 3.69%. Analysis, found: C 82.06; H 9.83; N 3.77%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.24 (s, 9H); 1.50 (s, 11H); 1.66 (bs, 4H); 2.39 (bs, 4H); 4.48 (s, 1H); 6.79 (d, 1H); 7.32 (m, 6H); 12.60 (s, 1H).

b) Preparation of compound (102), Table 1.

Compound (102), Table 1, m.p. 116-119° C., is obtained in analogy to Example 4 using compound (208), prepared according to Example 6a, instead of compound (202).

EXAMPLE 7 Process for the Preparation of Compound (105), Table 1.

a) Preparation of compound (207), Table 2.

8.29 g (97.33 mmol) of piperidine are added dropwise, at room temperature, to a solution of 4.71 g (44.43 mmol) of benzaldehyde in 50 ml of toluene; slight exothermicity is observed. The slightly yellow-coloured solution is boiled under reflux for 15 hours; approximately 1 ml of water is separated off using a water separator, and a solution of 10.0 g (42.3 mmol) of 3-(3-tert-butyl-4-hydroxy-phenyl)-propionic acid methyl ester in 15 ml of toluene is then added dropwise. The reaction mixture is boiled at reflux for a further hour and then cooled to room temperature; the solvent is distilled off using a vacuum rotary evaporator. Filtration of the residue over silica gel using ethyl acetate and crystallisation of the pure fractions from hexane yields 12.31 g (71%) of compound (207) (Table 2), m.p. 120-122° C. Molecular weight C₂₆H₃₅NO₃ (409.571). Analysis, calculated: C 76.25; H 8.61; N 3.42%. Analysis, found: C76.18; H 8.73; N 3.35%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.36 (s, 9H); 1.46 (m, 6H); 2.37 (bm, 4H); 2.41 (m, 2H) 2.66 (m, 2H); 3.53 (s, 3H); 4.33 (s, 2H); 6.49 (d, 1H); 6.86 (d,1 H); 7.23 (m, 5H); 12.60 (s, 1 H).

b) Preparation of compound (105), Table 1.

Compound (105), Table 1, is obtained as a slightly yellow oil, in analogy to Example 5 using compound (207), prepared according to Example 7a, instead of compound (206). Molecular weight C₂₂H₂₄O₄ (352.432). Analysis, calculated: C 74.98; H 6.86%. Analysis, found: C 75.08; H 6.89%. ¹HNMR (300 MHz, CDCl₃, ppm): 1.35 (s, 9H); 2.52 (t, 2H); 2.84 (t, 2H); 3.56 (s, 3H); 4.75 (s, 1H); 6.80 (d, 1H); 7.04 (d, 1H); 7.14 (m, 2H); 7.29 (m, 3H).

TABLE 1 no. compound 101

102

103

104

105

TABLE 2 no. compound 201

202

203

204

205

206

207

208

TABLE 3 no. compound 301

302

TABLE 4 no. compound 401

402

EXAMPLE 8 One-pot Process for the Preparation of Compound (102) (Table 1), Starting from Compound (202) (Table 2) using Various Catalysts.

A solution of 640 mg (1.89 mmol) of compound (202), prepared according to Example 2a, in 10 ml of dry toluene is degassed using argon, and the catalyst given in the Table and 348 mg (7.56 mmol) of formic acid are then added. The autoclave is flushed with carbon monoxide and sealed, and a carbon monoxide pressure of 8 bar is then applied. The reaction mixture is maintained at 110° C. for 4 hours. After cooling to room temperature, the reaction mixture is poured into water and extracted three times using ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated using a vacuum rotary evaporator. Filtration of the residue on silica gel using ethyl acetate and crystallisation of the pure fractions from isopropanol yields compound (102) (Table 1), m.p. 116-119° C. The results are collated in Table 5.

TABLE 5 amount of yield of compound Ex. catalyst catalyst [mol %] (102) in % 8a Pd(PPh₃)₄ 2.5 92 8b Pd(OAc)₂/2PPh₃ 2.5 99 8c Pd(OAc)₂/2PPh₃ 0.25 82 8d

0.1 70 8e

0.1 80 8f

0.1 90 8g

0.1 90 8h

0.1 90 8k

0.1 90 8l

0.1 95 8m

0.1 95 8n

0.1 95 

What is claimed is:
 1. A process for the preparation of compounds of formula I

wherein, when n is 1, R₁ is naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl, each of which is unsubstituted or substituted by fluorine, hydroxy, C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈ alkylthio, di-(C₁-C₄alkyl)amino, phenyl, benzyl, benzoyl or by benzoyloxy or R₁ is a radical of formula II or III

when n is 2, R₁ is phenylene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl or by fluorine; or is —R₆—X—R₇—, R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di-(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV

wherein R₁ is as defined above for the case where n=1, R₆ and R₇ are each independently of the other phenylene or naphthylene each unsubstituted or substituted by C₁-C₄alkyl, R₈ is C₁-C₈alkyl, R₉ is hydroxy,

C₁-C₁₈alkoxy or

R₁₀ and R₁₁ are each independently of the other hydrogen, CF₃, C₁-C₁₂alkyl or phenyl, or R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C₁-C₄alkyl groups; R₁₂ and R₁₃ are each independently of the other hydrogen or C₁-C₁₈alkyl, R₁₄ is hydrogen or C₁-C₁₈alkyl, R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

C₁-C₂₅alkoxy; C₂-C₂₅alkoxy interrupted by oxygen, sulfur or by

C₁-C₂₅alkylthio, C₇-C₉phenylalkyl, C₇-C₉phenylalkoxy, unsubstituted or C₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substituted phenoxy; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkoxy; di(C₁-C₄alkyl)amino, C₁-C₂₅-alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

C₁-C₂₅alkanoyloxy; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

C₁-C₂₅alkanoylamino, C₆-C₉cycloalkylcarbonyl, C₆-C₉cycloalkylcarbonyloxy, benzoyl or C₁-C₁₂alkyl-substituted benzoyl; benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy;

R₂₄ is hydrogen, C₁-C₄alkyl, or unsubstituted or C₁-C₄alkyl-substituted phenyl, R₂₅ and R₂₆ are hydrogen, C₁-C₄alkyl or phenyl, with the proviso that at least one of the radicals R₂₅ and R₂₆ is hydrogen, R₂₇ and R₂₈ are each independently of the other hydrogen, C₁-C₄alkyl or phenyl, R₂₉ is hydrogen or C₁-C₄alkyl, R₃₀ is hydrogen, unsubstituted or C₁-C₄alkyl-substituted phenyl; C₁-C₂₅alkyl; C₂-C₂₅alkyl interrupted by oxygen, sulfur or by

C₇-C₉phenylalkyl unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups; or C₇-C₂₅phenylalkyl interrupted by oxygen, sulfur or by

and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups, R₃₁ is hydrogen or C₁-C₄alkyl, R₃₂ is hydrogen, C₁-C₂₅alkanoyl; C₃-C₂₅alkanoyl interrupted by oxygen, sulfur or by

C₂-C₂₅alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group; C₆-C₉-cycloalkylcarbonyl, thenoyl, furoyl, benzoyl or C₁-C₁₂alkyl-substituted benzoyl;

R₃₃ is hydrogen or C₁-C₈alkyl, R₃₄ is a direct bond, C₁-C₁₈alkylene; C₂-C₁₈alkylene interrupted by oxygen, sulfur or by

C₂-C₂₀alkylidene, C₇-C₂₀phenylalkylidene, C₅-C₈cycloalkylene, C₇-C₈bicyclo-alkylene, unsubstituted or C₁-C₄alkyl-substituted phenylene,

R₃₅ is hydroxy, $\left\lbrack {{—O}^{-}\frac{1}{r}M^{r +}} \right\rbrack,$

C₁-C₁₈alkoxy or

R₃₆ is oxygen, —NH— or

R₃₇ is C₁-C₁₈alkyl or phenyl, M is an r-valent metal cation, X is a direct bond, oxygen, sulfur or —NR₁₄—, n is 1 or 2, p is 0, 1 or 2, q is 1, 2, 3, 4, 5 or 6, r is 1, 2 or 3, and s is 0, 1 or 2, which process comprises reacting a compound of formula V

wherein R₁ and n are as defined above, R₂, R₃, R′₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl, unsubstituted or C₁-C₄alkyl-substituted C₅-C₈-cycloalkyl; C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁-C₂₅alkanoyloxy, C₁-C₂₅alkanoylamino; C₃-C₂₅alkanoyloxy interrupted by oxygen, sulfur or by

C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₁₂alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R′₄ or the radicals R′₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R′₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R′₄ is additionally a radical of formula VI

wherein R₁ is as defined above for the case where n=1, with carbon monoxide in the presence of a catalyst.
 2. A process according to claim 1, wherein, when n is 2, R₁ is phenylene or —R₆—X—R₇—, R₆ and R₇ are phenylene, X is oxygen or —NR₁₄—, and R₁₄ is C₁-C₄alkyl.
 3. A process according to claim 1, wherein R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl; C₂-C₁₈alkyl interrupted by oxygen or by sulfur; C₁-C₁₈alkoxy; C₂-C₁₈alkoxy interrupted by oxygen or by sulfur; C₁-C₁₈alkylthio, C₇-C₉phenylalkyl, C₇-C₉phenylalkoxy, unsubstituted or C₁-C₄alkyl substituted phenyl; phenoxy, cyclohexyl, C₅-C₈cycloalkoxy, di(C₁-C₄-alkyl)amino, C₁-C₁₂alkanoyl; C₃-C₁₂alkanoyl interrupted by oxygen or by sulfur; C₁-C₁₂alkanoyloxy; C₃-C₁₂alkanoyloxy interrupted by oxygen or by sulfur; C₁-C₁₂alkanoylamino, cyclohexylcarbonyl, cyclohexylcarbonyloxy, benzoyl or C₁-C₄alkyl-substituted benzoyl; benzoyloxy or C₁-C₄alkyl-substituted benzoyloxy;

R₂₄ is hydrogen or C₁-C₄alkyl, R₂₅ and R₂₆ are hydrogen or C₁-C₄alkyl, with the proviso that at least one of the radicals R₂₅ and R₂₆ is hydrogen, R₂₇ and R₂₈ are each independently of the other hydrogen or C₁-C₄alkyl, R₂₉ is hydrogen, R₃₀ is hydrogen, phenyl, C₁-C₁₈alkyl; C₂-C₁₈alkyl interrupted by oxygen or by sulfur; C₇-C₉-phenylalkyl; or C₇-C₁₈phenylalkyl interrupted by oxygen or by sulfur and unsubstituted or substituted on the phenyl radical by from 1 to 3 C₁-C₄alkyl groups, R₃₁ is hydrogen or C₁-C₄alkyl, R₃₂ is hydrogen, C₁-C₁₈alkanoyl; C₃-C₁₂alkanoyl interrupted by oxygen or by sulfur; C₂-C₁₂-alkanoyl substituted by a di(C₁-C₆alkyl) phosphonate group; C₆-C₉cycloalkylcarbonyl, benzoyl,

R₃₃ is hydrogen or C₁-C₄alkyl, R₃₄ is C₁-C₁₂alkylene, C₂-C₈alkylidene, C₇-C₁₂phenylalkylidene, C₅-C₈cycloalkylene or phenylene, R₃₅is hydroxy,

or C₁-C₁₈alkoxy, R₃₆ is oxygen or —NH—, R₃₇ is C₁-C₈alkyl or phenyl, and s is 1 or
 2. 4. A process according to claim 1, wherein, when n is 1, R₁ is phenanthryl, thienyl, dibenzofuryl, unsubstituted or C₁-C₄alkyl-substituted carbazolyl; or fluorenyl, or R₁ is a radical of formula II

wherein R₁₉, R₂₀, R₂₁, R₂₂ and R₂₃ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylthio, phenyl, benzoyl, benzoyloxy or

R₂₉ is hydrogen, R₃₀ is hydrogen, phenyl or C₁-C₁₈alkyl, R₃₁ is hydrogen or C₁-C₄alkyl, and R₃₂ is hydrogen, C₁-C₁₂alkanoyl or benzoyl.
 5. A process according to claim 4, wherein R₁₉ is hydrogen or C₁-C₄alkyl, R₂₀ is hydrogen or C₁-C₄alkyl, R₂₁ is hydrogen, fluorine, hydroxy, C₁-C₁₂alkyl, C₁-C₄alkoxy, C₁-C₄alkylthio, phenyl or —O—CH₂—CH₂—O—R₃₂, R₂₂ is hydrogen or C₁-C₄alkyl, R₂₃ is hydrogen or C₁-C₄alkyl, and R₃₂ is C₁-C₄alkanoyl.
 6. A process according to claim 1, wherein R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₂₅alkyl, C₇-C₉phenylalkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl; unsubstituted or C₁-C₄alkyl-substituted C₅-C₈cycloalkyl; C₁-C₁₂alkoxy, C₁-C₁₂alkylthio, C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁-C₁₈alkanoyloxy, C₁-C₁₈alkanoylamino; C₃-C₁₈alkanoyloxy interrupted by oxygen, sulfur or by

C₆-C₉cycloalkylcarbonyloxy, benzoyloxy or C₁-C₈alkyl-substituted benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉ or —(CH₂)_(q)OH or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV

R₈ is C₁-C₆alkyl,

R₁₀ and R₁₁ are methyl groups or, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring unsubstituted or substituted by from 1 to 3 C₁-C₄alkyl groups; R₁₂ and R₁₃ are each independently of the other hydrogen or C₁-C₈alkyl, and q is 2, 3, 4, 5 or
 6. 7. A process according to claim 1, wherein at least two of the radicals R₂, R₃, R₄ and R₅ are hydrogen.
 8. A process according to claim 1, wherein R₃ and R₅ are hydrogen.
 9. A process according to claim 1, wherein R₂, R₃, R₄ and R₅ are each independently of the others hydrogen, fluorine, hydroxy, C₁-C₁₈alkyl, C₇-C₉phenylalkyl, phenyl, C₅-C₈cycloalkyl, C₁-C₆alkoxy, cyclohexylcarbonyloxy or benzoyloxy, or furthermore the radicals R₂ and R₃ or the radicals R₃ and R₄ or the radicals R₄ and R₅, together with the carbon atoms to which they are bonded, form a benzo ring, R₄ is additionally —(CH₂)_(p)—COR₉, or, when R₃ and R₅ are hydrogen, R₄ is additionally a radical of formula IV, R₉ is hydroxy or C₁-C₁₈alkoxy, and R₁₀ and R₁₁ are methyl groups or, together with the carbon atom to which they are bonded, form a C₅-C₈cycloalkylidene ring.
 10. A process according to claim 1, wherein R₂ is C₁-C₁₈alkyl or cyclohexyl, R₃ is hydrogen, R₄ is C₁-C₄alkyl, cyclohexyl, —(CH₂)_(p)—COR₉ or a radical of formula IV, R₅ is hydrogen, R₉ is C₁-C₄alkyl, R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a cyclohexylidene ring, and p is
 2. 11. A process according to claim 1, wherein R₂ is C₁-C₁₈alkyl or cyclohexyl, R₃ is hydrogen, R′₄ is C₁-C₄alkyl, cyclohexyl, —(CH₂)_(p)—COR₉ or a radical of formula VI, R₅ is hydrogen, R₉ is C₁-C₄alkyl, R₁₀ and R₁₁, together with the carbon atom to which they are bonded, form a cyclohexylidene ring, and p is
 2. 12. A process according to claim 1, wherein the catalyst is a metal catalyst.
 13. A process according to claim 12, wherein the metal catalyst is a metal catalyst that forms a complex with carbon monoxide.
 14. A process according to claim 12, wherein the metal catalyst is a transition metal catalyst.
 15. A process according to claim 14, wherein the transition metal catalyst is a titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum or copper catalyst.
 16. A process according to claim 14, wherein the transition metal catalyst is a titanium, vanadium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel or palladium catalyst.
 17. A process according to claim 1, wherein the ratio of molar quantities of the compound of formula V to carbon monoxide is from 1:1 to 1:5000. 